'Alien' Wasp Kills Whole Forests

It's a tidy system in which the adult wasps pick up the nematodes and distribute them along with their larvae, forming sort of a search and destroy network.

"In the Southern Hemisphere it has been a silver bullet," Hoebeke says. "It has kept the wasp population under control."

That's a dramatic change from just a few years ago, when the wasp was destroying trees by the thousands.

But would the same strategy work here? Experts think it's promising, but the situation here is much more complex than it was to the south. Our forests are more diversified, as well as our wasp population, and no one wants to wipe out all wasps. After all, they eat many other harmful insects, and they provide food for a wide range of animals.

There's always the concern that introducing a "bio-control agent," even a tiny nematode, could backfire. But at this point that's about the only thing that looks promising.

Hopefully, Hoebeke says, it's not already too late. The forests in this country are already under attack by beetles, fungus and all sorts of burrowing animals. In Alaska, for example, it is possible to drive for miles through dead spruce trees, killed by beetles that move across the landscape like an invisible plague.